R example of modelling with HiGHS solver and ompr framework

r_highs_ompr_example.R

#######
### This is a minimal example of using HiGHS solver in R with the help of ROI and ompr packages.
#######
## SETUP BEGIN
pti <- c("ompr.roi","ompr","highs","devtools")
pti <- pti[!(pti %in% installed.packages())]
if(length(pti) > 0){
  install.packages(pti) 
}

if(!("ROI.plugin.highs" %in% installed.packages())){
  devtools::install_gitlab("roigrp/solver/roi.plugin.highs")
}
## SETUP END

library(ROI.plugin.highs)
library(ompr.roi)
library(ompr)

## Model taken from https://dirkschumacher.github.io/ompr/

result <- MIPModel() |>
  add_variable(x, type = "integer") |>
  add_variable(y, type = "continuous", lb = 0) |>
  set_bounds(x, lb = 0) |>
  set_objective(x + y, "max") |>
  add_constraint(x + y <= 11.25) |>
  solve_model(with_ROI(solver = "highs"))
get_solution(result, x)